Transcriber’s Notes Texts printed in italics and bold face in the source document have been transcribed between _underscores_ and =equal signs=. Small capitals have been replaced with ALL CAPITALS. More Transcriber’s Notes may be found at the end of this text. [Illustration: Copyright, 1907, by Doubleday, Page & Company ALLIGATOR MISSISSIPPIENSIS. (After Ditmars.) (Reproduced by Permission of Doubleday, Page & Company.)] The Alligator and Its Allies By Albert M. Reese, Ph.D. Professor of Zoölogy in West Virginia University Author of “An Introduction to Vertebrate Embryology” _With 62 Figures and 28 Plates_ G. P. Putnam’s Sons New York and London The Knickerbocker Press 1915 COPYRIGHT, 1915 BY ALBERT M. REESE The Knickerbocker Press, New York PREFACE The purpose of this volume is to bring together, in convenient form for the use of students of zoölogy, some of the more important details of the biology, anatomy, and development of the Crocodilia. For obvious reasons the American Alligator is the species chiefly used. In the first chapter the discussion of the alligator is largely the result of the personal observations of the author; the facts in regard to the less familiar forms are taken from Ditmars and others. The description of the skeleton, with the exception of short quotations from Reynolds, is the author’s. The chapter on the muscular system is a translation from Bronn’s _Thierreich_, and the author has not verified the descriptions of that writer. The description of the nervous system is partly the author’s and partly taken from Bronn and others. The chapters on the digestive, urogenital, respiratory, and vascular systems are practically all from descriptions by the author. The chapter on “The Development of the Alligator” is a reprint, with slight alterations, of the paper of that title published for the author by the Smithsonian Institution. The bibliography, while not complete, will be found to contain most of the important works dealing with this group of reptiles. The author is grateful to Mr. Raymond L. Ditmars and to his publishers, Messrs. Doubleday, Page & Co., and Messrs. Sturgis & Walton, for the use of a number of plates; to the Macmillan Company and to the United States Bureau of Fish and Fisheries for the same privilege; to the National Museum for photographs of the skull of the gavial; and to the Smithsonian Institution for the use of the plates from researches published by them and included herein. Proper acknowledgment is made, under each borrowed figure, to the author from whom it is taken. MORGANTOWN, W. VA. _May 1, 1915._ CONTENTS PAGE CHAPTER I THE BIOLOGY OF THE CROCODILIA 1 CHAPTER II THE SKELETON 46